It's hard to be at all scientific so I won't.
Last year we made a big effort to be healthy, and stuck to a "no drink in the week" rule. It happened that we also seemed to reduce intake a lot at weekends, oddly. Now, there's no way I can describe my self as "fit", but last year was also my strongest year on the bike, I was climbing and generally staying at speed much better/longer. I just can't say for sure if the two are remotely linked, but I don't have another explanation readily to hand.
(This year's been a disaster mind so far with illness etc).